


The Doomfanger Diaries

by Catsitta



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell (Undertale), Angst, Animal Instincts, Animal Transformation, Childhood, Coming of Age, Drama, F/M, Family, Family Issues, Friendship, Growing Up Together, Mage Reader, Magic, Monsterphobia, Nature Versus Nurture, Pre-Relationship, Reader Is Not Chara (Undertale), Reader Is Not Frisk (Undertale), Reader and Papyrus both start the fic at 13, Reader is Doomfanger (Undertale), Trust Issues, Turned into a cat trope, Underfell Doomfanger (Undertale), Underfell Papyrus (Undertale), Underfell Sans (Undertale), no beastiality
Language: English
Status: In-Progress
Published: 2021-02-28
Updated: 2021-03-05
Packaged: 2021-03-12 18:53:54
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 2,484
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29764068
Author URL: https://archiveofourown.org/users/Catsitta/pseuds/Catsitta
Summary: You’re only thirteen when a routine magic lesson goes horribly wrong. Waking up in the Underground, where monsterkind was imprisoned by your ancestors, was bad enough. Being trapped in the shape of a cat just made it worse. Resigned to die a horrible death, alone in the cold, salvation comes in the shape of a skeleton.Underfell | Papyrus/Reader | Mage Reader
Relationships: Papyrus & Sans (Undertale), Papyrus (Undertale) & Reader, Papyrus (Undertale)/Reader
Comments: 31
Kudos: 75





	1. Dear Diary...

“Are you ready?”

You beamed up at the instructor and nodded, your dangling legs swinging as you sat on a tall wooden stool at the front of the class. There were eight other young teens watching with the usual mix of wide-eyed interest and blinking boredom. Going on one’s first spirit journey was an important milestone in a young mage’s education, as it was a major step in discovering one’s True Path. Some of the greatest mages to ever live could even dreamwalk and cross impossibly great distances over the astral plane. Of course, there were risks to this kind of magic—any magic, really. But the Gate College was inherently difficult and dangerous, as it was quite easy to leave bits of oneself behind in a different plane of existence if one was careless.

At thirteen, you and your peers were apprentices getting your first tastes of advanced magicks, and discovering affinities. Some would go on to specialize in a single college, while others would be low level generalists. And a select few would become archmages and show mastery of multiple branches of study. Above even them were the Council of Seven—the leaders of the Mage Guild. Of course, guild politics weren’t exactly the most intriguing thing to young students, not when they were barely discovering that they may have a knack for lighting fires or levitation.

“I can see your eagerness, Apprentice, but it is time for you to calm yourself,” the greyed instructor said. There was a hint of amusement in his sonorous voice. You swallowed and nodded, gaze flickering to the sapphire pin denoting him as a Master Blue Mage. “Breathe in and close your eyes. Meditation is key to success. Let your mind be clear of all distractions. Listen to nothing but my voice.” Blue mages often had an affinity for Movement and Gate magic. That little fact reminded you of the color of soul that rested behind your ribs, tucked safely away. Maybe you’d be one of the greats that would master traversing time and space! 

However long away that would be…

First you had to clear your mind and focus and pass this lesson.

The first spirit journey was always brief and guided by a Master. It allowed one a deeper understanding of the self with less risk of becoming lost outside of it. The Master acted as the anchor, ready to pull the Apprentice back into the physical realm should anything go awry. There were stories of the consequences of a failed spirit journey. Souls left wandering the astral plane, the body comatose. Children and adults alike going mad. Rare though these occurrences were, each was a warning toward caution.

You drew in long breaths, familiar herbal remedies flooding your lungs, until you were aware of nothing save your heartbeat. Steady and slow. Then, there was a warmth behind your sternum, someplace between bone and that rhythmic pulse of your lifesblood, and it swelled and pulled, pushed and ebbed, like waves against the hull of a ship, until it flooded through every vein like a whisper. You saw blue. You felt blue. You were...blue. You let the blue that was you drag you deeper and deeper until you sank impossibly deep beneath the surface, until blue became the deepest of indigo, almost indistinguishable from the black of the abyss. 

“Follow me. Trust me.”

Yes.

And then, quite suddenly, you were no longer consumed in blue, but caught in a haze of steely mists and starlight. Before you was a falcon carved of constellations and moonbeams, steadily beating within his constructed chest a pulsating heart of indigo. His Soul. The falcon tilted his head and the deep voice of your instructor emerged from his peak, “How delightful! It is not often I see an Apprentice with a fully realized astral form, much less on their first spirit walk.” It was at that moment you became aware of your non-human shape. And some very non-human impulses. Your new tail and whiskers twitched at the prospect of pouncing upon this fine feast of a bird. 

“We will remain here for a brief time for you to acclimate to the feeling of your spirit being outside of your physical form and then we shall return to our bodies. Now, look down, careful now. Don’t slip and fall!”

The temptation of a hunt was wrangled into submission and you peered down as instructed. You could see your body! The falcon fluttered down to perch on the desk, “Join me down here if you can. Do not worry if you are unable.” Intangible muscles coiled in your powerful hind legs. Too easy! Your feline form was made for leaping! But as you prepared to jump down, a flicker unlike starlight drew your eye. An ear swiveled. Whiskers twitched. The impulse to chase down the tiny movement was undeniable. Your instructor’s outcry was lost in the roar of false blood through sky-spun flesh. All you heard was _chase chase chase_ like a summons.

Your Soul sang as you hunted Purpose. 

_Go go go._

The very human part of You wrestled for control, but Instinct drove your paws onward, darting from star-to-star. Fear welled up but was quashed by Reason. If you lost yourself to Terror you could become lost forever, swallowed by the aether. Movement from above sent your strides hurtling faster, further. You were distantly aware of a voice begging you to ground yourself. Then suddenly, impact and the flutter of wings. 

“Apprentice! Listen to my voice. You are experiencing The Calling, and you are far too inexperienced to make that Journey yet. It is time to come back. Your connection to the astral plane is overwhelming, I can tell, but do not allow it to consume you. Remember your teachings. Breathe in. Remember who you are. Where you are from. And let us return to your body before you become unanchored.”

For a moment, it all seemed quite sensible. 

But as the falcon dug his claws into your ghostly fur, sensible went out the window and broke its neck. Instinct ripped from your throat in a hiss and silver claws slashed across the falcon’s chest, scattering stardust and shards of moonglass. You kicked his stunned form off with your back feet. The falcon floundered, his Soul weeping fat drops of blue, and a flailing wing caught you in the face, sending you staggering back. 

You didn’t expect to slip. With a yowl you tried to sink your claws into the constellations but found no purchase. The falcon gave a cry and tried to snare your nape, but his injuries impaired him. 

The world bled white.

And all you heard and felt was a steady chant of Rightness. As if magic itself dragged you into the heart of a supernova so that you could bear witness to the birth of a star.


	2. I'm a long way from home

Cold.

You were cold. 

Cold and wet and shivering.

Sleep sticky eyes peeled open, awareness hazy and blurred. You were supposed to go on your first spirit walk today. Had something gone...amiss? The sight of snow and the pervasive chill soaking your frame brought the day’s events into jarring clarity. The lesson had gone wrong. Horribly, awfully, terribly wrong! Oh god, would you get expelled from the school and exiled from your coven for attacking an instructor like that? It wasn’t on purpose. You didn’t mean to. Surely they would understand. 

But first...where were you?

What were you?

A yowl ripped from your chest as you realized you were in a distinctly feline form. Sodden white fur clung to clumsy, kitten limbs as you scrambled free of the snow poff you’d been dozing in. For a blink you reassured yourself that you were merely in your astral form, that you weren’t really a cat, but that delusion lasted all thirty seconds. Your surroundings lacked the dream-like quality and you very much felt the deepening chill. 

Calm. You had to be calm. 

Shapeshifting was one of the most advanced techniques of the Animal College and generally temporary. There were stories of Master shapeshifters, however, who chose to stay in their alter forms permanently. It was not too terribly uncommon for a young mage to accidentally change shape when certain kinds of spells went awry. Sometimes they would be attempting to summon a familiar or, like you, have some mishap during a spirit walk. Without willfully maintaining the spell, surely it would wear off soon...Of course, you did just wake up, and usually being unconscious disrupted that kind of magic, but the likelihood of it being anything more than a brief and awful inconvenience were slim.

However, sorting out how you ended up the shape of a cat, did not explain where you were or how you got there. As, apparently, instead of returning to your body, you ended up...elsewhere. You flicked your paws and trudged through the snow, mind whirling. You fell in the astral plane. Your mind and spirit should be lost right now, but instead, you had a physical body. Which implied a planar transition. Impressiveness aside—to discover an affinity for Gate and Animal Magicks in one bizarre conglomeration of events—this was bad. Unlike when dabbling strictly within Movement magic, where one could end up anywhere if a spell went awry, Gate magic added an element of anywhen. 

You peered helplessly at unfamiliar pines in their strange, overly neat rows, then up towards the sky for guidance, hoping that come nightfall, your fledgeling knowledge of astronomy would help orient you. But to your horror, there was no sun or clouds or stars or moon. There wasn’t even a sky. Instead there was stone as far and as high as you could see. Fat flakes fell from somewhere even higher above into a fathomless void as black as an ink dark sea. The trees and the rest of the environment were illuminated as if it were high noon, even casting shadows. False light—mage light?—offered a facsimile of natural sunshine without a detectable source.

Was this some kind of top secret underground bunker? The air and earth felt rich with mana. A perfect place for the coven to retreat to should there be a need. If you popped underneath the school, then no doubt somebody would find you in no time at—

You froze.

Howls pierced the air.

Instincts not your own kicked in and you darted to a tree. Except, as you tried to scale it, your strength flagged and failed. Your limbs were too heavy and unfamiliar and just wouldn’t cooperate. The howls grew closer. You sank your claws desperately into the wood, biting down the urge to whine when you couldn’t pull yourself higher. This was bad. BAD. You looked around for somewhere, anywhere, to hide. A strange construction caught your eye. It was ramshackle and made of cardboard and uneven planks of wood, but it was better shelter than sitting in the snow. You kicked off the tree and squeezed into one of the boxes, sneezing once at the reek of mildew...or possibly mold. There WAS an empty mustard bottle in here.

As the barks and howls continued to grow closer, you dared a peek through a small gap in the cardboard. Your heart near failed you when it was not a pack of dogs that barged past, but a pack of dog monsters. They were hideous, feral looking beasts with matted fur and frothing mouths and wild eyes. If not for the armor they wore and the weapons they held in their paws, one might have assumed them completely lacking in sentience. 

“Cat,” one of the dogs barked. 

“Cat,” echoed another. 

You were dead. You were going to die brutally mauled by dog monsters, and nobody would ever know. Not with the Underground being sealed off by the Seven centuries ago after the War! There was no escaping the Barrier...okay, maybe there was a way, but you were never the best at history when thaumatology was far more interesting. All you knew for certain, because it was practically preached from the picture books of your childhood, was that the only way for the Barrier to be broken, was for seven souls—one for every mage that sealed the Underground—to be sacrificed. The stories always came with a grim warning. That should the Barrier fall, there would be War once more, and mages would need to rise against the threat of monsterkind. 

“Cat. Cat. Cat!” chanted the dogs.

You curled up in the corner of your cardboard sanctuary and despaired. If they found you, they would surely kill you for sport. And if the shapeshifting spell failed before they found you, they’d kill you with extra relish AND steal your Soul.

Desperately, you tried to pull on your magic, at the mana around you, anything to save yourself, but your magery failed you. In this form, it was like there was a wall between your and your magic, and while in theory there was a door somewhere on said wall, it was nowhere in sight. 

“We’re on patrol!” a female voice scolded. “Ignore the cat. Cat isn’t important.”

There were yips and growls and a general murmur of agreement, “Smell tasty cat. Smell tasty bones. Chase later.”

“Later?”

“Later.”

After a long beat, the barks and howls passed, and grew more distant. But there was the implication they would return. Patrols meant paths and they would likely return. It wasn’t safe to stay here. Swallowing down the urge to stay curled up and hidden (it would be a shoddy hiding place once you were human again), you crept from the box and began moving as fast as you could away from the dogs. As the cold and fear burned through your rapidly tiring feline form, a bitter kind of resignation filled you. Monsters would want you dead and any death they would offer would be cruel. At least if you found some place quiet and safe to die, out of sight, they wouldn’t be able to harvest your soul. 

_Maybe I can get out of here. Dying can’t possibly be the best option—_

The ground suddenly surged up and swallowed you whole. Wait. No. You were flung up. You were...in a net? You had sprung a hidden net trap! Animal instinct warred with human despair. Trapped. You were trapped. Oh god this wasn’t how you wanted it to end at all. You struggled and writhed and kicked and tried to squeeze free, but only managed to entangle yourself further. Eventually, you tired, and fell limp in exhausted defeat. 

You couldn’t willfully turn back into a human.

You were trapped Underground with humanity’s greatest (albeit mostly forgotten) enemy.

And you were going to likely freeze to death in some kind of primitive hunting trap.

How could this possibly get worse?!

“YOU’RE NOT A HUMAN!”

**Author's Note:**

> Should I be starting a new fic? No. Was this living rent free in my head for months? Yes. Do I have an outline of the whole fic? Yeeeep. Fortunately, this one shouldn't be overly long. 
> 
> It is a coming of age and friendship overcoming prejudice kind of fic. Will there be romance? A hint near the end when everyone are very much adults and our reader is very much /not/ a fuzzy feline (in case that has you worried). ^_^ But mostly, this is focused on two characters growing up. The expectations of their relative societies. And the roles we play. 
> 
> Hopefully, this odd little fic is enjoyable~
> 
> AUTHOR'S NOTES:
> 
> \+ The magic system is RPG based, and I actually used the guidebook for said RPG when structuring my 'magic system' for the mages.
> 
> \+ Many colleges of magic have overlap and some require master of other colleges to even begin to learn. Such as the most entry level Gate Spells are some of the most advanced Movement Spells, etc.
> 
> \+ Monster magic and human/mage magic are two different systems, however, mages can have affinities (often determined by their soul type) for certain kinds of magic. And mages are often classified by both their power level (Apprentice/Master/ETC) as well as their soul color (red, blue, etc).


End file.
